Microsoft is aware of and investigating a remote code execution vulnerability that affects Windows Print Spooler and has assigned CVE-2021-34527 to this vulnerability. This is an evolving situation and we will update the CVE as more information is available. The vulnerability is dubbed PrintNightmare.
A remote code execution vulnerability exists when the Windows Print Spooler service improperly performs privileged file operations. An attacker who successfully exploited this vulnerability could run arbitrary code with SYSTEM privileges. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.
An attack must involve an authenticated user calling RpcAddPrinterDriverEx().
Please ensure that you have applied the security updates released on June 8, 2021, and see the FAQ and Workaround sections in this CVE for information on how to help protect your system from this vulnerability
CVE-2021-34527 applies to Windows and Windows Server all the way back. It’s not known if earlier versions of Windows are going to be patched.